Lucas A. Meyer
2022-07-07
Content stuck in my computer is nearly worthless.
Literate programming can help create high-quality reproducible, documented code.
Donald E. Knuth proposed literate programming in a 1984 article.
Jupyter implements the literate programming paradigm, but generating high-quality mass-consumable output (articles, websites) requires additional tools.
\usepackage{ifthen}@for, @whileQuarto® is an open-source scientific and technical publishing system built on Pandoc.
The name “quarto” comes from the format of a book or pamphlet printed with eight pages of text, four to a side, then folded twice to produce four leaves.
The earliest known European printed book, the Sibyllenbuch (Gutemberg, c.1452), was done in the quarto format. Shakespeare’s plays, too!
With Quarto, you can:
You can install Quarto on Linux, Windows and Mac.
About 75% of data scientists use Python through Jupyter notebooks.
With some scripting, you can use Pandoc on .ipynb files to generate papers, HTML, PowerPoint, etc.
You just need to learn Pandoc and shell scripting.
graph TD
A[.ipynb] --> B(("Pandoc"))
B ----> E[.doc]
B ----> H[.pptx]
B --> C[.md]
B --> D[.tex]
D --> F((Xetex))
C --> I((Hugo))
F --> G[.pdf]
I --> J[.html]
style B fill:#FF6655AA
style F fill:#88ffFF
style I fill:#88ffFF
All you need to use Quarto is to add some YAML (mostly simplified Pandoc configurations) to a .qmd file.
ipynb + YAML = .qmd.
This keeps the configuration and content in the same file. You can then render the outputs using quarto render <file.qmd> in the command line.
graph TD
Q[.qmd] --> A
subgraph Quarto
A[.ipynb] --> B(("Pandoc"))
B --> C[.md]
B --> D[.tex]
D --> F((Xetex))
C --> I((Hugo))
style B fill:#FF6655AA
style F fill:#88ffFF
style I fill:#88ffFF
end
B ----> E[.doc]
B ----> H[.pptx]
F --> G[.pdf]
I --> J[.html]
Quarto files always start with a YAML front-matter.
The YAML configuration determines what’s the output format of your document. A few popular output options are html, pptx, docx, and pdf.
You can use a single source file to generate multiple output types.
For example, the YAML on the right will generate a PowerPoint file and a Revealjs presentation.
Write content in Markdown.
Quarto’s Markdown supports figures, tables, bibliography, etc.
It also supports lots of extra features, like diagrams with mermaid and GraphViz, and even LaTeX equations:
\[ E = mc^2 \]
The best thing about Quarto is that you can use it to run any code that you would be able to run in a Python notebook.
You can use mermaid to create diagrams.
The diagram in this and in previous sections were created with mermaid.
flowchart TD
A[Hard] -->|Text| B(Round)
B --> C{Decision}
C -->|One| D[Result 1]
C -->|Two| E[Result 2]
This code runs the first regression in Wooldridge’s Econometrics:
\[ \text{wage} = \alpha + \beta_1 \times \text{educ} + \epsilon \]
| coef | s.e. | t | p-value |
|---|---|---|---|
| -0.9049 | 0.685 | -1.321 | 0.187 |
| 0.5414 | 0.053 | 10.167 | 0 |
To create slides, you create sections with #, titles with ##, and bullets with -.
To generate a presentation from a .qmd file, add format: pptx to the YAML front-matter.
Quarto will use the pandoc PowerPoint rules to render the content from the .qmd into .pptx.
The “pandoc rules” limit the flexibility to create PowerPoint presentations. Quarto has better presentation support for revealjs and beamer.
The rules are available at:
https://pandoc.org/MANUAL.html#powerpoint-layout-choice
title and author#).md source contains :::: {.columns} and only text contentBy adding a reference-doc entry to your YAML, you can tell Quarto (and pandoc) to use a file as a template for the format of your presentation.
The “Slide Master” needs to contain layouts named as per the previous slide (e.g. “Comparison”).
This allows you a lot of flexibility in the design of your slide deck, even if it is for just the small number of layouts that were listed in the previous slide.
You can control fonts, add background images, page numbering, etc.
Let’s say you’re presenting a project about population dynamics but you don’t know which world leaders are coming to the conference.
On the presentation day, you learn that Belgium, China, Brazil, India, Japan and Nigeria are attending.
You can use Python or R to automatically generate slides.
The next slides/sections were generated using the code below:
df_dr = pd.read_csv("data/dr.csv.gz", compression="gzip")
df_pop = pd.read_csv("data/pop_brackets.csv.gz", compression="gzip")
years = [2000, 2025, 2050, 2075, 2100]
regions = ["Belgium", "China", "Brazil", "India", "Japan", "Nigeria"]
for name in regions:
display(Markdown(f"## Age and Population Pyramids for {name}"))
display(Markdown(f'<div class="columns">'))
display(Markdown(f'<div class="column">'))
plot_dependency_ratio(df_dr[df_dr.Location == name])
display(Markdown(f'</div>'))
display(Markdown(f'<div class="column">'))
plot_population_pyramid_series(df_pop[df_pop["Location"]==name], years)
display(Markdown(f'</div>'))
display(Markdown(f'</div>'))
---
title: "Quarto with Python"
format: html
# revealjs:
# incremental: false
# theme: [simple, revealjs-customizations.scss]
# title-slide-attributes:
# data-background-image: images/data-viz-bg.jpg
# data-background-size: contain
# data-background-position: right
author: Lucas A. Meyer
date: 2022-07-14
---Adding or changing the format to html will create a website.
I reused some of the content of this presentation to create two scholarly-looking articles. The purpose of the articles is just to show how easy it is to generate them with Quarto, they don’t contain original research. Quarto add cross-reference, citations and bibliography support to Markdown.
The relevant files are:
Citations don’t work on presentations, but are easy to add to articles.
You need to reference a BibTex file in the YAML front-matter bibliography: references.bib. Quarto supports any of the 8000+ Citation Style Languages and will generate the “References” section automatically.
You can cite by using [@citation-name] in your text. Please check the article .qmd source and the PDF and DOCX outputs.
Generating footnotes is also easy. Using [^ref] links to a footnote, and [^ref: content of the footnote] generates its content1.
You can also write books with quarto. From the same collection of .qmd files, Quarto can generate:
Two recent examples are:
This is a free book, and you can see the Quarto (source) that generated it.
This is another free book, and you can see the Quarto (source) that generated it.
I think Quarto is more helpful for a team that already uses Git with Python notebooks or LaTeX to write articles.
Microsoft Word collaboration through SharePoint and Teams is easier than Git and Quarto… but it’s not reproducible.
Quarto adds features to Python notebooks without detracting anything. You just need a few YAML lines.
Quarto allowed me to have a scriptable, Python-based blog. I wrote code to post new articles to Twitter and LinkedIn.
Great for RevealJS. For PPT, render process => long edit cycle. Useful for:
graph TD
P[Pre-scripts] --> Q
style P fill:#AA99FF
Q[.qmd] --> A
subgraph Quarto
A[.ipynb] --> B(("Pandoc"))
B --> C[.md]
B --> D[.tex]
D --> F((Xetex))
C --> I((Hugo))
style B fill:#FF6655AA
style F fill:#88ffFF
style I fill:#88ffFF
end
B ----> E[.doc]
B ----> H[.pptx]
F --> G[.pdf]
I --> J[.html]
E --> X[Post-scripts]
H --> X
G --> X
J --> X
style X fill:#AA99FF